punctuation mark, 1540s, from Latin colon "part of a poem," from Greek kolon (with a long initial -o-) "part of a verse," literally "limb, member" (especially the leg, but also of a tree limb), also, figuratively, "a clause of a sentence," from PIE root *(s)kel- (3) "bent, crooked" (see scoliosis). Meaning evolved from "independent clause" to punctuation mark that sets it off.